The present invention relates to control apparatuses for hybrid electric vehicles.
Examples of known hybrid electric vehicles include one in which an electric current is supplied to a motor from each of a battery and a generator driven by an engine, and a driving wheel is driven by driving torque outputted from the motor.
For such a hybrid electric vehicle, there is proposed a technique (related art) in which when an accelerator pedal pressing speed is equal to or higher than a given value, an electric current generated by a generator by starting an engine is added to an electric current supplied from a battery, and the resulting electric current is supplied to a motor, thereby sharply increasing driving torque in response to a sudden accelerator pedal pressing operation (see Japanese Patent No. 3767103).
Thus, a rush current flowing into the motor from the battery is suppressed, thereby reducing the load on the battery and ensuring responsiveness of driving torque outputted from the motor.
However, in the above related art, there is apprehension that the larger the number of times the engine is started by sudden accelerator pedal pressing, the lower the fuel efficiency will be.
In fact, it is known that the lower the motor coil temperature (the motor temperature), the larger the rush current flowing into the motor from the battery, and the higher the motor coil temperature, the smaller the rush current.
Therefore, when the motor coil temperature is low, the engine is preferably started at an early stage to supply an electric current to the motor from the generator, thereby suppressing the rush current.
However, when the motor coil temperature is high, the rush current is originally small, thus reducing the necessity for starting the engine at an early stage to suppress the rush current.